JP2009-291069A discloses a linear motor that displaces a tubular yoke and a rod relative to each other in an axial direction by attracting a permanent magnet disposed on an outer peripheral surface of the rod using a moving magnetic field generated around a coil disposed on an inner peripheral surface of the yoke. In this linear motor, force attracting the permanent magnet functions as thrust for displacing the tubular yoke and the rod relative to each other in the axial direction.